Frederik Zietzschmann

This study evaluates the capability of three passive samplers (PS) to enhance the monitoring of per- and polyfluoroalkyl substances (PFAS) in industrial wastewater. Effluent from a textile manufacturer, an industrial laundry, and a semiconductor facility (all ≥10,000 m³/a discharge) was sampled over the course of two work weeks. Passive sampling included a polar organic chemical integrative sampler (POCIS), a Speedisk sampler (SD), and a flow-through tube passive sampler (TPS), while an automated aqueous sampler obtained continuous composite wastewater samples. Composite samples revealed fluctuating concentrations of up to 18 different PFAS (varying by site) with total loads from 0.12 mg/day (semiconductor manufacturer) to 8.8 mg/day (industrial laundry). Notably, the PS detected up to 19 additional PFAS compared to aqueous samples, revealing multiple representatives of legacy PFAS as well as precursor compounds (6:2 FTAB, 6:2 FTS), differing by site. Quantitative assessments from PS in the complex industrial matrices remained inconclusive and need further examination. This study highlights the in situ enrichment potential of PS as sensitive and low-maintenance qualitative tools. When applied in parallel, PS and continuous composite aqueous sampling offer complementary advantages and improved insight in qualitative and quantitative monitoring of PFAS emissions from industrial sources, with relevance for regulatory surveillance.

We present a versatile flow-through tube passive sampling device (TPS), with a controllable feedwater volumetric flow, that can be calibrated in situ against the feedwater load of organic micropollutants (OMPs). This semipassive approach has the advantage of a determinable water load feeding the sampling device. The design of the TPS allows for new sampling scenarios in closed piping while providing stable and controlled sampling conditions. The calibration referencing an OMP's feedwater load can describe the uptake behavior from wastewater treatment plant effluent with potentially highly fluctuating OMP concentrations. The TPS and its load-dependent calibration under realistic environmental conditions proves possible for a variety of organic trace substances in a challenging matrix. Nine of the 20 monitored representative OMPs could be calibrated load-dependently, leading to a good agreement between the calculated concentration from the TPS and the average concentration of corresponding direct measurements. Due to the simple measuring principle and the membrane-less discs, many influencing factors such as diffusion, turbulence, and lag time phenomena can be neglected. The TPS could support the existing online measurement analytics in a (process-) water treatment plant by delivering integrated water concentrations for discharge monitoring.